As an exhaust gas measurement device of this kind, there is one adapted to measure carbon monoxide (CO), total hydrocarbons (THC), nitrogen oxides (NOx), carbon dioxide (CO2) and the like contained, for example, in engine exhaust gas exhausted from an engine of an automobile (see Patent Literature 1).
Specifically referring to the exhaust gas measurement device, as shown in FIG. 4, this exhaust gas measurement device 3 includes two flow lines branched from an introduction flow line 31 to which sample gas containing exhaust gas is introduce, and one of the two flow lines is used as a sensor flow line 32 which is provided with a plurality of gas analyzers 322 for measuring various components and the other is used as a bypass flow line 33 which is configured to bypass the excessive sample gas which is unnecessary for the measurement. It is noted here that the phrase “to bypass the (excessive) sample gas” means “to guide the (excessive) sample gas to flow through the bypass flow line separated from the sensor flow line” in this description.
In this exhaust gas measurement device 3, in order to perform an accurate measurement in each of the gas analyzers 322, it is necessary to introduce sample gas into each of the gas analyzers 322 at a specific set pressure value. Therefore, it is configured such that the pressure thereof is to be kept at the set pressure value in a state that a predetermined quantity or more of the sample gas is rendered to flow through the bypass flow line 33 by a pressure regulator 331 provided on the bypass flow line 33. Further, the exhaust gas measurement device 3 is adapted to measure a pressure of the sample gas controlled by the pressure regulator 331 and provided with a continuous measurement impossibility display part 42 for displaying that the measurement of various components contained in the sample gas is not being performed accurately so that the measurement is impossible any more in a case where the measurement pressure value to be measured is largely apart from the set pressure value.
Then, a user, upon seeing that impossibility of the continuous measurement is displayed by the continuous measurement impossibility display part 42, checks, for example, a clogging of a filter 311 provided on the introduction flow line 31 and a pump for sucking the sample gas, which can be considered as a cause of the pressure control by the pressure regulator 331 being impossible, and after removing a cause of such a malfunction, the exhaust gas is to be measured again.
In this exhaust gas measurement device, however, a user can be informed of an abnormality of the exhaust gas measurement device only in the case where the filter is clogged or an ability of the pump is reduced to such a degree that the measurement of the exhaust gas cannot completely be continued. In other words, since the user is informed of an abnormality of the device only after such a large problem that the measurement of the exhaust gas cannot be continued occurs, the user cannot expect a time when the measurement becomes impossible in advance so that it cannot be helped to interrupt the measurement of the exhaust gas half-finished in some cases. Then, the measurement data interrupted in the middle of the measurement of the exhaust gas has to be abandoned due to such as a problem with continuation of a measurement condition and this may result in that the measurement of the exhaust gas then executed becomes useless.